Flexible vertebral spacer

Abstract

A flexible implant system for positioning a flexible spacer between adjacent vertebrae including and interbody spacer and an insertion instrument. The interbody spacer including a central axis, a lateral axis, a top surface positioned generally parallel to the central axis and a plurality of hinge sections extending generally perpendicular to the central axis. A plurality of notches making up the plurality of hinge sections adjacent the top surface that permit the interbody spacer to flex. The interbody spacer further including a groove extending along a lateral side surface, generally parallel to the central axis. An insertion instrument includes a proximal end, a distal end and a tongue extending from the proximal end to the distal end along a non-linear path. The groove slidably engages the tongue to guide the interbody spacer from the proximal end to the distal end along the non-linear path.

What is claimed: 
     
       1. An implant system for positioning a flexible spacer between adjacent vertebrae, the implant system comprising:
 a flexible interbody spacer including a spacer body that defines a top surface and a bottom surface each configured to engage one of the adjacent vertebrae, opposed side surfaces extending between the top surface and the bottom surface, a lateral axis extending between the opposed side surfaces and substantially parallel to the top and bottom surfaces, and a plurality of hinge sections that permit the interbody spacer to flex about the lateral axis, the interbody spacer defining a height measured from the top surface to the bottom surface at a location between adjacent ones of the plurality of hinge sections, and the interbody spacer defining a width perpendicular to the height, the width measured from one of the opposed side surfaces to the other of the opposed side surfaces at a location between the adjacent ones of the plurality of hinge sections, the width being greater than the height, and the interbody spacer including a mating surface extending along one of the opposed side surfaces, wherein each of the plurality of hinge sections is defined by a notch that extends into the spacer body from the bottom surface and terminates within the spacer body prior to reaching the top surface; and 
 a guide rail including a guide rail body that defines a proximal end, an opposed distal end, an inner surface that faces either the top or bottom surface of the interbody spacer when the interbody spacer is received by the guide rail, the guide rail body further including a track extending between the proximal end and the distal end along a non-linear path, the mating surface slidably engagable with the track to guide the flexible interbody spacer from the proximal end to the distal end along the non-linear path; wherein the inner surface defines a curvature about an axis that is parallel to the lateral axis when the mating surface is slidably engaged with the track. 
 
     
     
       2. The system of  claim 1 , wherein the mating surface comprises a groove. 
     
     
       3. The system of  claim 1 , wherein the mating surface comprises a recess. 
     
     
       4. The system of  claim 3 , wherein the recess comprises shape selected from the group consisting of slot with round tip, T-shaped, and triangular. 
     
     
       5. The system of  claim 1 , wherein the track comprises a channel. 
     
     
       6. The system of  claim 5 , wherein the channel comprises a base member and opposing side walls. 
     
     
       7. The system of  claim 1 , wherein the hinge sections comprise demineralized bone segments. 
     
     
       8. The system of  claim 1 , wherein the top surface and the bottom surface comprise a plurality of teeth. 
     
     
       9. The system of  claim 1 , wherein the flexible interbody spacer further comprises a front end and a back end. 
     
     
       10. The system of  claim 9 , wherein the front end comprises a sloped nose. 
     
     
       11. The system of  claim 1 , wherein the flexible spacer comprises a plurality of rigid segments and a spanning member which is inserted through the plurality of rigid segments. 
     
     
       12. The system of  claim 1 , wherein the guide rail instrument further comprises an engagement mechanism located at the proximal end. 
     
     
       13. The system of  claim 12 , wherein the engagement mechanism comprises a fastener. 
     
     
       14. The system of  claim 12 , wherein the guide rail instrument further comprises a drive mechanism, the drive mechanism being operatively connected to the engagement mechanism. 
     
     
       15. The system of  claim 1 , wherein the notch extends into the spacer body in a direction that is perpendicular to both the axis and the lateral axis. 
     
     
       16. A flexible interbody spacer for positioning between adjacent vertebrae, the flexible spacer comprising:
 a top vertebra contacting surface and an opposed bottom vertebra contacting surface each configured to engage one of the adjacent vertebrae, and opposed side surfaces each extending between the top vertebra contacting surface and the bottom vertebra contacting surface, the top vertebra contacting surface spaced from the bottom vertebra contacting surface in a first direction; 
 a front end and an opposed back end extending between the top and bottom vertebra contacting surfaces, a central axis extending between the front end and the back end, and a lateral axis extending between the opposed side surfaces and perpendicular to the central axis, the spacer defining a length from the front end to the back end along the central axis; and 
 at least one hinge section positioned between the front end and the back end, each of the at least one hinge sections allowing the spacer to flex about a respective axis that is: 1) perpendicular to the first direction and 2) parallel to the lateral axis; 
 wherein each of the respective axes is positioned closer to the top vertebra contacting surface than the bottom vertebra contacting surface, each of the at least one hinge sections extends into the flexible spacer from the bottom vertebra contacting surface and terminates within the flexible spacer between the bottom surface and the top vertebra contacting surface, and the flexible spacer is devoid of any hinge sections that allow the flexible spacer to flex about a respective axis that is positioned closer to the bottom vertebra contacting surface than the top vertebra contacting surface. 
 
     
     
       17. The flexible spacer of  claim 16 , wherein at least one of the top vertebra contacting surface and the bottom vertebra contacting surface comprises a rough surface. 
     
     
       18. The flexible spacer of  claim 17 , wherein the rough surface comprises a plurality of teeth. 
     
     
       19. The flexible spacer of  claim 16 , wherein the front end comprises a sloped nose. 
     
     
       20. The flexible spacer of  claim 19 , wherein the sloped nose tapers to a rounded tip. 
     
     
       21. The flexible spacer of  claim 16 , wherein the rear end comprises at least one recess configured to engage with an insertion tool. 
     
     
       22. The flexible spacer of  claim 16 , wherein each of the at least one hinge sections comprises a notch and each notch has a depth defined as the distance the notch extends into the flexible spacer in the first direction from the bottom vertebra contacting surface toward the top vertebra contacting surface. 
     
     
       23. The flexible spacer of  claim 22 , wherein the flexible spacer defines a height that is measured from the top vertebra contacting surface to the bottom vertebra contacting surface along a line perpendicular to the central axis, and the notch extends from the bottom vertebra contacting surface through more than half of the height of the flexible spacer toward the top vertebra contacting surface. 
     
     
       24. The flexible spacer of  claim 22 , wherein the first direction is substantially perpendicular to the central axis. 
     
     
       25. The flexible spacer of  claim 22 , wherein the notch extends through both of the opposed side surfaces. 
     
     
       26. The flexible spacer of  claim 22 , wherein the first direction is perpendicular to the lateral axis. 
     
     
       27. The flexible spacer of  claim 16 , further comprising a mating surface configured to slidably attach to a guide rail instrument. 
     
     
       28. The flexible spacer of  claim 27 , wherein the mating surface comprises a configuration comprising one of tongue-and-groove, rail-and-slot, dove tail, and various keyed geometries. 
     
     
       29. The flexible spacer of  claim 16 , wherein the flexible spacer comprises a plurality of rigid segments and the at least one hinge section comprises a spanning member which is inserted through the plurality of rigid segments. 
     
     
       30. The flexible spacer of  claim 29 , wherein the spanning member comprises material selected from the group consisting of silicone, polyethylene, ultra-high molecular weight polyethylene, braided cable, suture, wire, and braided high-strength fibers. 
     
     
       31. The flexible spacer of  claim 29 , wherein the spanning member allows the flexible spacer to flex or rotate along the central axis of the flexible spacer. 
     
     
       32. The flexible spacer of  claim 16 , wherein the flexible spacer comprises material selected from the group consisting of polyether-ether-ketone (PEEK), porous PEEK, titanium, titanium alloys, metal alloys, foamed metal alloys, sintered metal alloys, ceramics, and sintered ceramics. 
     
     
       33. The flexible spacer of  claim 16 , wherein the flexible spacer comprises allograft bone. 
     
     
       34. The flexible spacer of  claim 33 , wherein the at least one hinge section comprises demineralized allograft bone allowing the flexible spacer to rotate or flex along the central axis. 
     
     
       35. The flexible spacer of  claim 34 , wherein the demineralized allograft bone is manufactured by a process selected from the group consisting of surface masking, necking, and drilling holes in a region to be demineralized. 
     
     
       36. The flexible spacer of  claim 33 , wherein the flexible spacer comprises a plurality of rigid segments made of allograft bone and the at least one hinge section comprises a spanning member made of allograft tendon which is inserted through the plurality of rigid segments. 
     
     
       37. The flexible spacer of  claim 36 , wherein the allograft tendon comprises material selected from the group consisting of Achilles tendon allograft, bone-patellar tendon-bone allografts, and fascia lata allografts. 
     
     
       38. The flexible spacer of  claim 16 , wherein the distance between the top vertebra contacting surface and the bottom vertebra contacting surface along a line perpendicular to the central axis defines a height. 
     
     
       39. The flexible spacer of  claim 38  wherein the height of the spacer varies along the central axis of the spacer. 
     
     
       40. The flexible spacer of  claim 38 , wherein the height of the spacer at the rear end is greater than the height of the spacer at the front end. 
     
     
       41. A guide rail instrument configured to position a flexible spacer between adjacent vertebrae, the guide rail instrument comprising:
 a guide rail body portion defining a proximal end and a distal end opposite the proximal end, the guide rail body portion having a non-linear shape so as to define a non-linear delivery path between the proximal and distal ends, the guide rail body portion further defining a track that extends between the proximal and distal ends along the non-linear delivery path, the track including a first end and a second end opposite the first end, wherein the flexible spacer enters the track at the first end, travels in a direction along the non-linear delivery path, and exits the track at the second end, the track configured to engage a corresponding mating surface of the flexible vertebral spacer, so as to allow the spacer to travel from the first end to the second end; and 
 an engagement mechanism including an engagement member that extends beyond both the distal end of the guide rail body and the second end of the track with respect to the direction, a drive mechanism opposite the engagement mechanism, and a drive body operably connecting the engagement member to the drive mechanism such that the drive body is configured to transfer a rotational force that is applied to the drive mechanism to the engagement member; 
 wherein the engagement member is configured to be driven through an exterior surface of one of the vertebrae such that the guide rail instrument is secured relative to the one of the vertebrae prior to insertion of the spacer between the adjacent vertebrae. 
 
     
     
       42. The rail instrument of  claim 41 , wherein the body portion has a substantially rectangular cross-section sized to deliver the flexible spacer between the adjacent vertebrae. 
     
     
       43. The rail instrument of  claim 41 , wherein the body portion has a substantially “C-shaped” cross-section. 
     
     
       44. The rail instrument of  claim 41 , wherein the track comprises a lip configured to slidably engage with corresponding grooves of the flexible spacer. 
     
     
       45. The rail instrument of  claim 41 , wherein the track comprises a configuration of tongue-and-groove, rail-and-slot, dove tail, or various keyed geometries. 
     
     
       46. The rail instrument of  claim 41 , wherein the mating surface is additionally configured to engage with a tissue retractor or a discectomy and endplate preparation instrument and deliver the tissue retractor or preparation instrument along a non-linear delivery path to a disc space. 
     
     
       47. The rail instrument of  claim 41 , wherein the engagement mechanism comprises a fastener. 
     
     
       48. The rail instrument of  claim 41 , wherein the direction is a first direction, and the drive mechanism extends beyond the proximal end with respect to a second direction that is opposite the first direction. 
     
     
       49. A kit for positioning a flexible spacer between adjacent vertebrae, the kit comprising:
 a plurality of flexible interbody spacers, each of the plurality of flexible spacers comprising: a spacer body including: 
 a top surface configured to engage one of the adjacent vertebrae, a bottom surface configured to engage another of the adjacent vertebrae, and opposed side surfaces extending between the top surface to the bottom surface, a front end, a back end, a central axis extending between the front end and the back end, a lateral axis extending between the opposed side surfaces such that the lateral axis is perpendicular to the central axis, a length measured from the front end to the back end along the central axis, and a height measured from the top surface to the bottom surface; a mating surface configured to slidably attach to corresponding surface on a guide rail instrument mating surface; and 
 at least one hinge section spaced along the length, each of the hinge sections allowing the spacer body to flex about the lateral axis, wherein each of the plurality of hinge sections is defined by a notch that extends into the spacer body from the bottom surface and terminates within the spacer body prior to reaching the top surface; and a guide rail instrument comprising: 
 a body portion having a non-linear shape, the body portion also comprising a distal end and a proximal end; 
 an engagement mechanism located at the distal end; and 
 the guide rail track configured to engage the flexible spacer mating surface on the plurality of flexible spacers. 
 
     
     
       50. The kit of  claim 49 , wherein the plurality of flexible spacers include spacer bodies of various sizes and shapes. 
     
     
       51. The kit of  claim 49 , wherein the engagement mechanism comprises a fastener. 
     
     
       52. The kit of  claim 49 , wherein the guide rail instrument further comprises a drive mechanism located at the proximal end and operatively connected to the engagement mechanism. 
     
     
       53. The kit of  claim 49 , wherein the flexible spacer mating surface and the guide rail mating surface comprise a configuration of tongue-and-groove, rail-and-slot, dove tail, or various keyed geometries. 
     
     
       54. The kit of  claim 49 , wherein the notch extends into spacer body in a direction that is perpendicular to both the central axis and the lateral axis.